Field of the Invention
This application is directed to dental accessories, and, more particularly, is directed to an apparatus and method for preventing backflow in saliva ejectors used for removing accumulated liquids and other materials from the mouth of a patient during dental procedures.
Description of the Related Art
A saliva ejector is an apparatus used by a dentist or a dental hygienist during dental procedures to evacuate saliva, blood and other debris from a patient's mouth. The saliva ejector includes a suction line and a low-volume saliva ejector tip. The saliva ejector tip is inserted into the patient's mouth with the ejector tip in the region of the material to be removed. Suction is applied via a suction line to evacuate the material from the patient's mouth and to discharge the evacuated material to a waste container. In accordance with acceptable dental practice, the saliva ejector tip is a single use device that is replaced after each patient. In contrast, the suction line may be replaced or cleaned only after the suction line has seen used with several patients. Unfortunately, this practice can result in fluids from a previous dental patient or from multiple previous patients remaining in the suction line when the saliva ejector is used on a subsequent patient.
A common dental practice is to have a patient close the patient's lips around the low-volume saliva ejector tip and expectorate to help evacuate the mouth. Closing the lips around the ejector tip can cause a decrease in the magnitude of the vacuum line negative pressure. The decrease in magnitude may allow the previously evacuated fluid remaining in the suction line to flow backwards into the patient's mouth. This backflow of fluid can carry oral contaminants such as blood, viruses, bacteria, and fungi from prior patients. Studies have found that oral bacteria can survive inside of the suction line. Furthermore, diseases, such as influenza, strep, and hepatitis B, can be passed to subsequent patients if material remaining in the suction line backflows into the patient's mouth.
In order to decrease the possibility of the backflow of fluids into a dental patient's mouth, dentists and hygienists routinely instruct patients not to close their lips around the saliva ejector tips so as to prevent a decrease in the negative magnitude of the vacuum line pressure. However, humans tend to close their lips around a straw when sucking, and the request to keep the lips apart during sucking is counter to this behavior. Moreover, even if a patient succeeds in overcoming the tendency to close his or her lips around the ejector tip, the saliva ejector tip may still get wedged in a position in the patient's mouth—for instance in the cheek folds—to block the end of the tip and cause a decrease in the negative magnitude of the vacuum line pressure, which can result in backflow.
Another approach for decreasing the chance of oral contaminants being passed from patient to patient is to clean or change the suction line after every patient. However, this approach is time consuming and is cost prohibitive. Furthermore, if the suction line is rinsed thoroughly with a germ killing rinse, any remaining rinse residue in the suction line may backflow into the mouth of a subsequent patient. This circumstance would be unpleasant for the dental patient or possibly dangerous depending on the caustic nature of the rinse.
It has been recognized in the art that cross-contamination between patients, for example, dental patients, can occur when evacuators (suctioning devices) attached to vacuum lines are used to remove such bodily fluids and contaminants. Various articles, guidelines and studies have addressed the potential for such cross-contamination including, for example: Possibility of Cross-Contamination Between Dental Patients by Means of the Saliva Ejector, C. M. Watson, R. L. S. Whitehouse, JADA, Vol. 124, April 1993; Backflow in Low-Volume Suction Lines: The Impact of Pressure Changes, G. Mann, T. Campbell and J. Crawford, JADA, Vol. 127, May 1996; Cross-Contamination Potential of Saliva Ejectors Used in Dentistry, J. Bargeau, et al., Journal of Hospital Infection, 1998: 40:303-11; and Guidelines for Infection Control in the Dental Health Care Setting—2003, Center for Disease Control, 2003, all of which are herein incorporated by reference to the extent not inconsistent with the present disclosure. Such cross-contamination can occur as vacuumed bodily fluids, contaminants or both can backflow from the vacuum line into the patient's mouth, body or both. Backflow can occur when flow is interrupted when a patient closes his or her mouth over the vacuum tip, thereby stopping flow or even overpowering the negative vacuum pressure by sucking on the tip.